Every time I try to create a rocket, it generally flies straight (i.e. my Atlantis Payload Orbital Xe3), with the exception of when it has detatchers and boosters, it flies around in circles and explodes (I.e. my Phoenix Heavy Launcher and Cyclone Enceladus Launcher). If anyone can give me advice or design ideas, please do so in this post.

P.S. I would also like to know how you could make stages for a multistaged rocket.